/*
 * Copyright © 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using Spring.Expressions;

namespace Spring.Objects.Factory.Config;

/// <summary>
/// Immutable placeholder class used for the value of a
/// <see cref="Spring.Objects.PropertyValue"/> object when it's a reference
/// to a Spring <see cref="IExpression"/> that should be evaluated at runtime.
/// </summary>
/// <author>Aleksandar Seovic</author>
[Serializable]
public class ExpressionHolder
{
    private IExpression expression;
    private string expressionString;
    private MutablePropertyValues properties;

    /// <summary>
    /// Creates a new instance of the
    /// <see cref="Spring.Objects.Factory.Config.ExpressionHolder"/>
    /// class.
    /// </summary>
    /// <param name="expression">The expression to resolve.</param>
    public ExpressionHolder(string expression)
    {
        expressionString = expression;
        this.expression = Spring.Expressions.Expression.Parse(expression);
    }

    /// <summary>
    /// Gets or sets the expression string.  Setting the expression string will cause
    /// the expression to be parsed.
    /// </summary>
    /// <value>The expression string.</value>
    public string ExpressionString
    {
        get { return expressionString; }
    }

    /// <summary>
    /// Return the expression.
    /// </summary>
    public IExpression Expression
    {
        get { return expression; }
    }

    /// <summary>
    /// Properties for this expression node.
    /// </summary>
    public MutablePropertyValues Properties
    {
        get { return properties; }
        set { properties = value; }
    }

    /// <summary>
    /// Returns a string representation of this instance.
    /// </summary>
    /// <returns>A string representation of this instance.</returns>
    public override string ToString()
    {
        return $"<{expressionString}>";
    }
}
